Intercommunicating system



June 12, 1934. K, CARROLL INTERCOMMUNICATING SYSTEM Original Filed July 21, 1924 2 Sheets-Sheet 1 QQ 8 m June 12, 19342 R L 1,962,298

INTER-C OMMUNICAT-ING SYSTEM Original Filed July 21, 1924 2 Sheets-Sheet 2 Patented JuneIZ, 1934 UNITED STATES 1,962,298 mnnconmomcs'rmc SYSTEM Howard K. Carroll, Chicago, 11]., assignor, by mesne assignments, to Teletype Corporation, a corporation of Delaware Application July 21, 1924, Serial No. 727,316

' Renewed August 7 1930 86 Claims.

The present invention relates to intercommunicating systems.

More particularly the invention relates to an intercommunicating system especially adapted for hotels, railway terminals or stations, banks, manufacturing establishments and the like, in which a number of telegraph typewriters are located at different points, and where it may be desired to communicate at will with any one or more of the remaining units in the system from any printer, leaving all the idle printers free to intercommunicate in any desired way.

The objects of the invention are vto provide a switching system for telegraph or signaling instruments in which any desired combination of printers may be connected in a common circuit, leaving the idle instruments free to be connected in any further desired combination, to provide a busy signalling system which will indicate at each station, the instruments that are busy; to provide remote motor control arrangements; and such other objects as may be attained by utilization of the various combinations and subcombinations set forth in the disclosure of the preferred embodiments of the invention as defined by the, terms of the appended claims.

' Referring to the drawings:

Figures 1 and 2 show in diagram the essential.

parts of the circuit arrangements for a system comprising four telegraph typewriters.

For convenience in description the stations will be designated stations A, B, C, and D. At each station there is located a telegraph typewriter unit preferably comprising a single contact transmitter and a single magnet receiver such, for example, as is disclosed in Patent 1,567,392, issued Dec. 29, 1925 to E. E. Ifleinschmidt. For each station a separate line circuit is provided which passes through all of the stations and which are designated lines A1 to D1 respectively. Eachopcrating line comprises three wires, two of which are receiver operating wires and the third is the busy signal and motor control wire.

The station apparatus at each station comprises a printing unit controlled by a selector magnet 1 controlling a printer, and connected in series with a transmitting contact 2 of a single contact transmitter, in conductors 3 and 4. Transmitting contact 2 is normally closed'and is preferably shunted by a condenser 5. The transmitter and receiver are driven by a motor 6. The

circuit of motor 6 is completed by conductor- 7 or to the negative terminal, and by conductor 8 through relay armature 9 when closed and conductor 10 to the positive terminal of a source of electrical energy.. Armature 9 is actuated by a spring and by a magnet 11 which is connected in series by conductor 12 through armature 13 when closed, to the positive and negative terminals of the electrical supply. Armature 13 is actuated by a spring and by a magnet 14, which is connected in a circuit from the negative terminal, through conductor 12 to conductor 15. At-station A conductor 3 passes 'through spring 16 of battery switch a in unactuated position to contact 17 and conductor A3 of operating line A1. Conductor 4 passes through spring 18, contact 19 in unactuated position, to conductor A4 of line A1. Conductor is connected to conductor A15 of line A1, and A15 is connected to spring 20 of switch (1. Switch 11 is provided with a sprin 21 which is connected to the negativeterminal of electrical energy through bus conductor 22. When switch a is actuated springs 16, 18. 20 and 21 will engage contacts 23, 24, 25 and 26 respectively. This shifts conductor 3 from conductor A: through spring 16 and contact 23, to conductor 27, through springs 28, contacts 29', balancing resistances 30, contacts 31, and springs 32 of switches b1 01 and d1 in series and from spring 32 of the last switch d1 through conductor 33 to contact 26; conductor 4 will be shifted from line A4 through spring 18 and contact 24 to the positive terminal of the source of electrical energy through bus conductor and conductors 15 and A15 will be connected through spring 20, contact 25 and a resistance 34 to positive bus 35. In additionto placing positive potential on conductors l5 and A15, engagement of spring 20 with contact 25 completes a circuit from bus 22 to bus 35 through a busy signal lamp 36.

The structure of each of the switches b1 01 and V (11 is exactly the same, and each is provided with a spring 26 and a contact 25 adapted to be engaged thereby to connect positive potential from bus 35 through resistance 34 to springs 20 when the respective switches are actuated. Each of the switches b1 to d1 is also provided with a busy lamp 36 individual thereto and connected between negative bus 22 and the spring 20. Contacts. 37 of the. switches b1 81 and (11 are connected respectively to the conductors B3, C3 and D3 of lines B1 C1 and D1 respectively; contacts 33 are connected to conductors B4, C1, and Di respectively, and springs 20 are connected to conductors B15, C15 and D15 respectively.

At stations B, C and D, the structure of battery switches 15, c and d is the same as the structure of the battery switch a at station A. The contacts 17 and 19 of switches b c and d are connected to conductors B1, B1, C3, C1, D3 and D1 respectively of lines B1, C1, and D1. At these stations switches (11, b1, and 01, the same as switch b1 at station A, are provided which have the contacts 36 and 37 thereof connected to conductors A3, A1, B5, B1, C5 and C1 respectively. Springs 20 of each of the switches a, b, c, d,.a1, b1, 01, and 61 are connected respectively to the conductors A15 B15 C15 and D15 of the respective lines; and conductors 3, 4, and 15 of the apparatus at each-station are connected to springs 16, 18 and 20 respectively of the battery switches a, b, c and d in the manner set forth in the detail description of the connections to switch a at station A. The local connections through switches a1, 01 and d1, (11, b1 and d1, and m,

.111 and 01 at stations B, C, and D are the same as the local connections through switches b1, 01, and d1 at station A and will be clear from the detail description of station A.

The arrangement is such that the actuation of battery switches a, b, c, or 11 will release line A1, B1, C1 or D1 respectively and the actuation of switches (11, b1, 01 or d1 at any station will give access of the particular station at which the switch is actuated to stations A, B, C, and D respectively.

With none of the stations operating, all of the parts will be in the position shown in the drawings, lamps 36 will all be extinguished, and the motors 6 will be at rest. The operator at station A seeing the lamps individual to the switches b1 c1 and d1 extinguished will be informed that the lines to stations B, C and D are available. He will then actuate switches a, b1, 01 and d1 throwing springs 16, 18, 20, and 21v into engagement with contacts 23, 24, 25, and 26 respectively, and springs 28 and 32 into engagement with contacts 37 and 38 respectively. Spring 20 will place positive potential on conductors A15, B15, C15 and D15 from contacts 25, and will cause all of the lamps 36 at station A to light in the local lamp circuits. At the same time current will flow over conductors A15, B15, C15 and D15 from positive bus 35 at station A through lamps 36 of all the switches at stations B, C, and D to negative bus conductors 22 at the various stations causing all the lamps to light and showing that all of the stations are I busy. Current will also flow over conductor 15 at each station from positive potential on conductors A15, B15, C15 and D15 through relay'windings 14 and conductors 12 to negative potential. Relays 14 will energize attracting armatures 13 and complete energizing circuits from conductors 7 and 8 to motors 6. All of the motors will now start into operation.

At the same time a series operating circuit is completed from positive bus 35 at station A, through contact 24, spring 18, conductor 4, selector magnet 1, transmitting contact 2, conductor 3, spring 16 of switch brcontact 23, conductor 27 spring 28, contact 38 and conductor B1 to station B; at station'B through contact 19 of switch b, spring 18, conductor 4, magnet 1, contact 2, conductor 3, spring 16, contact 17, conductor B3 back to station A; at station A through contact 37 andspring 32 of switch b1 to conductor 27 and spring 28 of switch 01. contact 38 and conductor C1 to station C; at station C through contact 19 of switch 0, spring 18, conductor 4, magnet 1, contact 2, conductor 3, spring 16, contact 17, conductor'Cs back to station A; at station A through contact 37 and spring 32 of switch b1 to conductor 27 and spring 28 of switch d1, contact 38 and conductor D1 to station D; at station D through contact 19 of switch d, spring 18, conductor 4, magnet I,

contact 2, conductor 3 spring 16, contact 17, conductor D3 back to contact 37 of switch d1 at station A; and then through spring 32 of switch (11, station A, conductor 33, contact 26, spring 21 to negative bus 22. All of the motors will now be operating and the receivers and transmitters'at each station are connected in aseries circuit. Any transmittermay now be actuated to transmit messages which will be recorded on all printers in the system.

The operator at station A new has control of all of the lines, and by restoring the proper ones of the keys b1, (21, or 121 to unactuated position he can eliminate any of the other stations at will.

Assuming that he desires to eliminate stations B and D, leaving only station C in circuit with station A, switches brand 011 are restored to unactuated position. The circuit above traced through switches b1 and d1 will then be shifted by springs 28 and 32 from contacts 37 and 38 to contacts 29 and 31, substituting balancing resistances 30 for the conductors B3 and B1 and Da' and D1 respectively. Springs 20 of switches b1 and 111 will be disengaged from contacts 25 removing positive potential from the lamps 36 individual thereto, and'from conductors B15 and D15. The circuit through B15 and D15 to the lamps 36 at switches b and (1, stations B and D, and to the relays 14 will be interrupted, the lamps individual to switches b, b1, (1, and d1 will be extinguished throughout the system, the energizing circuits from motors 6 at stations B and D will be interrupted by retraction of armatures 13, and these motors will come to rest. Lines B1 and D1 are in this manner entirely removed from the circuit and the series operating circuit is completed through resistances 30 at switches b1 and d1 station A. The resistance values of 30 are so chosen that no change in line current occurs when these resistance are substituted in the operating circuits in place of the lines A1, B1, C1 or D1. When station A desires to cut off the actuated switches are restored to unactuated position causing all the lights to extinguish and relays 14 to de-energize, thereby stopping the rotation of the motors 6 at the stations which have been controlled from A. It will be clear that at each station, lamps 36 will indicate the stations connected in operating circuits. Any station not in use 'ean seize the lines leading to any other stations not in use and separate series circuits may be established by simply closing the local battery switch a to d and corresponding switches a1 to d1 of the stations A to D not in operation. When station A is in communication with station C, station D can establish communication with station B by simply actuating keys d and b1; In like manner station C can communicate with stations B and D by actuating switches 0, b1 and d1 and can connect A in the circuit by closing switch on. If it is desired to eliminate any station the corresponding switches (21, b1 or 111 are restored to unactuated position.

An intercommunicating .printer system of maximum flexibility is provided in which any station may establish communication with any of the other stations or with any desired combination of the other stations, leaving the idle stations free to intercommunicate in any desired manner. Although only four stations are shown, it will be obvious that the stations may be increased to any desired number by adding the proper lines, battery and connecting switches, and it will further be obvious that the number of other stations to which any one station may have access can be varied by making suitable connections.

Having described preferred embodiments of the invention what is desired to be secured by Letters Patent and claimed as new is:

1. An intercommunicating system for telegraph apparatus comprising a plurality of stations, receivers at said stations, mechanical'switching mechanism at each station, and means including the switching mechanism at one of said stations for connecting any one or more of the receivers at others of said stations in a common communicating circuit.

2. An intercommunicating system for telegraph apparatus comprising a plurality of stations, a transmitter at one of said stations, receivers at the others of said stations, a common communicating circuit connecting said stations, mechanical switching mechanism at 'each of said stations, and means including the switching mechanism at said transmitter for connecting any one or more of said receivers in said common communicating circuit.

3. The system as set forth in claim 2 in which the common communicating circuit is a series loop through said transmitter and said receivers.

4. An intercommunicating system comprising a plurality of stations, a common communicating circuit connecting said stations, transmitting and receiving apparatus at each of said stations, mechanical switching mechanism ateach of said stations, means including the switching mechanism at one of said stations for connecting the apparatus at any one or more of the others of said stations in series in said common communicating circuit and means including a source of direct current for communicating between said connected stations.

5. An intercommunicating system comprising a plurality of stations, a common communicating circuit connecting said stations, transmitting and receiving apparatus at each of said stations, mechanical switching means at each of said stations for connecting the apparatus at any desired ones of the other stations in a common communicating circuit, means including the transmitter at one of said connected stations for transmitting code .combinations of direct current impulse conditions over said circuit and means responsive to said impulses received over said circuit for operating the receiver connected thereto.

6. A telegraph switching system comprising a plurality of stations, a line individual to each of said stations, and means at each of said stations for connecting the line individual thereto and any one or more of the others of said lines in a series circuit.

7. A telegraph switching system comprising a plurality of stations and a common communicating circuit connecting said stations, and mechanical means at each idle station for interconnecting any desired ones of the remaining idle stations over said conmion communicating circuit.

8. A telegraph switching system comprising a plurality of stations, a common communicating circuit connecting said stations, and control means at one of said stations for connecting any one or more of said stations over said common communicating circuit and for supplying electrical signalling energy to said common circuit, said control means comprising a mechanical switching mechanism.

9. A telegraph system comprising a plurality of stations; a common conmiunicating circuit,

mechanical switching means for interconnecting any desired ones of said stations over said common communicating circuit; and means for indicating at each station the ones of said stations connected in said circuit.

10. The combination as set forth in claim 9 in which said last mentioned means comprises a signal lamp at each station individual to each of said other stations. 1

11. 'A telegraph system comprising a plurality of stations, means for interconnecting any one of said stations with any other one or more of said stations in a communicating circuit; and a motor at one of said stations controlled by said interconnecting means.

12. A telegraph switching system comprising a plurality of stations, means at each station for seizing any one or more of said stations; and a drive motor at each of said stations started into operation when its station is seized, and

arrested in operation when its station is freed.

13. In a telegraph signalling system, a plurality of stations, receivers at said stations, a signalling circuit individual to each of said stations, and means at each of said stations for connecting any one or more of the receivers at said other stations in a common signalling circuit including said individual circuits.

at said transmitter for controlling any one of said individual circuits or connecting any combination thereof in a series loop circuit.

16. In a telegraph signalling system a plurality of stations, a transmitter at one of said stations,

receivers at the other of said stations, a circuit individual to each of said receivers, and means at said transmitter for controlling any one of said individual circuits or connecting any combination thereof in a series loop circuit, said loop circuit including said transmitter and said receivers.

17. In a telegraph signalling system, a plurality of stations, transmitting and receiving apparatus at each of said stations, a circuit individual to each of said stations and means at any one of said stations for connecting any other one of said circuits or combinations thereof in a common series circuit.

18. A telegraph signalling system, a plurality of stations, transmitting and receiving apparatus at each of said stations, a circuit individual to each of said receiving apparatus and connected thereto and switching means at said stations for selectively connecting said circuits.

19. In a telegraph switching system, a plurality of receiving stations, normally non-operating receivers at each of said stations and mechanical switching means at any one of said stations for selectively starting said receivers into operation.

20. In a telegraph signalling system, a plurality a" of stations, a drive motor at each of said stations normally at rest and means at any one of said stations for selectively starting saidmotors into operation.

21. In a telegraph signalling system,.a plurality of stations, a drive. motor at each of said stations normally at rest and means at any one of said stations for selectively starting and stopping said motors.

22. In a telegraph signalling system, a plurality of stations, a normally non-operating motor individual to each of said stations, a circuit individual to each of.said motors, and means for selectively connecting said circuits and for starting pre-determined ones of said motors into operation. 7

23. In a signalling system, a plurality of stations, switches for selectively interconnecting said stations in varying combinations, a motor at each station, motor relays for controlling said motors, and common mechanical means for operating said station controlling relays and said motor connecting switches whereby said motors are started into operation with the interconnection of said stations.

24. In a signalling system, a plurality of stations, switches for interconnecting said stations in varying combinations, a motor at each station, motor switches for controlling said-motors, common mechanical means for simultaneously operating said station connecting switches and said motor connecting switches whereby said motors are started into operation simultaneously with the interconnection of said stations, and a pilot lamp at each motor switch and under control of said switch for indicating the condition of its associated motor.

25. In a signalling system, a plurality of stations; lines associated one with each of said stations; link circuits associated one with each of said stations and normally disconnected from all of said lines; sources of current connected in said link circuits; and switches at each station for connecting said link circuits with said lines.

26. In a signalling system, a plurality of signalling stations having signalling apparatus thereat; a series link circuit normally disconnected from the signalling apparatus at all of said stations; a source of current; a switch for connecting said source and the signalling apparatus of a first of said stations in series with said link circuit; other circuit switches for connecting the signalling apparatus of others of said stations with said link circuit and the'signalling apparatus of said first station; and means for maintaining a uniform value of operating current in said series link circuit irrespective of the number of signalling apparatus connected therein. a

27. In a signalling system, a plurality of stations; a link circuit; means for connecting a variable number of said stations in series in said link circuit; a source of energy for supplying signalling current to said circuit; and means operated as each station is connected to said link circuit for maintaining a uniform value of signalling current in said link circuit irrespective of the number of stations connected therein.

28. In a telegraph switching system, a plurality of stations; a common communicating circuit for connecting said stations; control means comprising mechanical switching mechanism at one of said stations for connecting one or more of said stations over said common communicating circuit; a source of energy for supplying current to said circuit; and means operative as the stations are connected in said circuit for maintaining a uniform electrical signalling energy at all times in said common circuit.

29. In an intercommunicating system having telegraph apparatus comprising a plurality of stations; a transmitter at one of said stations; receivers at the other of said stations; 9. common circuit connecting said stations; mechanical switching mechanism at each of said stations; means including the switching mechanism at said transmitter for connecting any one or more of said receivers in said common circuit; and means for maintaining the energy supply on said telegraph communicating circuit at a fixed value irrespective of the number of stations connected in said circuit.

30. In an intercommunicating system comprising a plurality of stations; a communicating circuit connecting said stations; transmitting and receiving apparatus at each of said stations; mechanical switching mechanism at each of said stations; means at one of said stations for connecting the apparatus at that station and at any one or more of the other stations in series in said common communicating circuit; and means including a source of direct current for supplying energy to said circuit.

31. A signalling switching system comprising a plurality of stations; and means at each station for connecting that station and any one or more of the other stations in a series circuit; a source of direct current for. supplying communicating energy to said circuit; and means for maintain-- ing the direct current in said circuit at a constant value irrespective of the number of stations connected in said circuit.

32. In a telegraph switching system, a transmitting station; a plurality of receiving stations; line wires individual to each of said receiving stations and means at the transmitting station for connecting any one or more of the receiving stations in a common signalling system with said transmitting station and including the said line wires of the connected receiving stations.

33. In a telegraph signalling system, a plurality of stations; a transmitter at one of said stations; receivers at the others of said stations;

a circuit individual to each of said receivers; and

means at said transmitter for connecting any combination of said individual circuits in a series circuit.

34. In a telegraph system, a plurality of stations; a transmitter at one of said stations; re-

ceivers at the others of said stations; a circuit individual to each of said receivers; and means for connecting any combination of said individual circuits in a series loop circuit including said transmitter and receivers.

35. In a telegraph signalling system; a plurality. of stations; transmitting and receiving apparatus at each"of said stations; a circuit individual to each of said stations; and means at any one of said stations for connecting any combination of said circuits in a common series circuit.

36. In a telegraph system, a plurality of stations; transmitting apparatus at one of said stations; and receiving apparatus at the others of said stations; a circuit individual to each of said circuit receiving apparatus and connected thereto; and switching mechanism at said transmitting apparatus for selectively connecting said individual circuits in series.

37. A printing telegraph system comprising a transmitting station; a plurality of receiving stations; signalling lines interconnecting said transmitting station and said receiving stations; manually operable switching means at said transmitting station for interconnecting said, transmitting station with said receiving stations; means at each of said stations for transmitting and receiving impulses; and further means operated by said manually operable switching means preventing substantial change in resistance in the signalling circuit.

38. A printing telegraph exchange system comprising a transmitting station; a plurality of receiving stations; .a plurality of lines interconnecting said transmitting station and said receiving stations; means at each of said stations for transmitting and receiving impulses over said signalling line, said signalling line being of a predetermined resistance and means responsive to the interconnecting of another of said stations for reducing the resistance of each of said lines to compensate for increased resistance of said line extending to each station in series.

39. In a signalling system, a first station; a plurality of other stations; a signalling line con necting said first station with each of the other stations; automatic telegraph apparatus at each of said stations; and means for electrically connecting said first station to any one of said other stations; said means being simultaneously operative for changing the signal line characteristics to compensate for the line resistance between stations.

40. In a signalling system, a plurality of sta tions; a signalling circuit connecting each of said stations; telegraph apparatus at each of said stations; and means at one of said stations for excluding one other of said stations from said signalling circuit; said means modifying the characteristics of said signalling circuit to compensate forv the resistance of the excluded station.

41. In a telegraph system, a plurality of stations; a circuit connection between said stations; said circuit connection including a resistance; means including said circuit connection for signailing between said stations; and means at said resistance for selecting and connecting another station for communication and for simultaneously eliminating said resistance to compensate for the resistance of the added station.

42. A printing telegraph intercommunicating system comprising a first station, a plurality of other stations; a plurality of telegraph subscriber lines interconnecting said first station and said other stations; manually operable link circuits at each station for interconnecting said stations; means at each of said stations for transmitting and receiving impulses; and means at said first station responsive to the interconnection of any of said subscriberlines for compensating for the increase in resistance in the signalling circuit including said transmitting and said receiving apparatus.

43. A printing telegraph intercommunicating system comprising a first station; a plurality of other stations; a plurality of telegraph subscriber lines interconnecting said stations; means at each of said stations for transmitting and receiving impulses over said lines; said subscriber lines being of a predetermined resistance; and means responsive to the interconnection of any of said lines for reducing the resistance of the subscribers lines to compensate for increased resistance of said line in series.

44. In a telegraph system, a plurality of stations; circuits extending through all the stations equal in number to the number of stations; receiving apparatus at each station normally connected in the circuits corresponding to that station; a resistance corresponding to each of the other stations and normally connected to the circuit corresponding to that station and means to substitute for any resistance, the circuit and receiving apparatus of another station.-

45. In a telegraph system, a first station; a link circuit at said station; other stations; resistances in said link circuit at said first station one for each of said other stations; telegraph signalling sets, one at each station; lines connecting said first station to each of said other stations; a key at said first station for forming a signalling cir-' cuit comprising said link circuit at said first station, said telegraph signalling set at said first station and said resistances; and other keys at said first station for substituting in said link circuit one of said other stations in place' of one of said resistances.

46. In a telegraph system, a first station, a link circuit at said station; other stations, receiving apparatus at each station, a circuit corresponding to each station and normally connected to the receiving apparatus at that station; resistances at the first station one corresponding to each of the other stations; a key at the first station for forming a circuit comprising the link circuit and all of said resistances; and other keys at said first station for substituting in said link circuit for each of said resistances one of the circuits and its associated receiving apparatus. 1

47. A printing telegraph system comprising a plurality of stations; a manually operated link circuit at one of said stations for interconnecting said stations; manual switches in said link circuit; means at each of said stations for transmitting and receiving impulses; and means associated with said switches for starting and stopping the said transmitting and receiving means at con- ,nected stations.

48. A printing telegraph system comprising a plurality of stations; a manually operable link circuit at one of said stations for interconnecting said stations; manual switches in said link circuit; normally non-operating means at each of said stations for transmitting and receiving impulses; and means controlled by said switches for rendering operative said transmitting and receiving means.

49. A printing telegraph system comprising a plurality of stations; manually operable link-circuit devices for interconnecting said stations; signalling means at each of said stations for sending and receiving isochronous signals; and normally idle motor-means for driving said signalling means, said motor means being started by said link-circuit devices.

50. A printing telegraph system comprising a control station; a plurality of other stations; a plurality of lines interconnecting said control station and said other stations; manually operable link mechanism at said control st..tion'for interconnecting said stations; means at each of said stations for sending and receiving isochronous codes of signals; normally stopped motors for driving said means; and starting means for said motors under control of said manually operable link mechanism.

51. A printing telegraph system comprising a control station; a plurality ,of other stations; a plurality of lines interconnecting said control station and said other stations; a link circuit comprising in par; a set of manually operable switches at said control station for interconnecting said control station with said other stations; means at each 01. said stations for sending and for receiving printing telegraph signals; a normally non-operating motor at each station for driving said means; and means responsive to the operation of said set oi switches for the interconnection of any of said stations for starting said motors thereat into operation. 1 t

52. A telegraph switching system comprising a first station, a plurality of other stations, lines from said first station to each of said other stations, switching means at said first station for seizing any one of said other stations, thereby establishing an intercommunicating connection, and drive motors at each of said other stations, each of said motors started into operation when its station is seized and arrested in operation when its station is freed.

53. A telegraph system including a plurality of telegraph stations, circuit connections between said stations, telegraph apparatus atsaid stations, motors at said stations for driving said telegraph apparatus, manually operable means for interconnecting the telegraph apparatus at said stations for communication purposes, and means associated with said manually operable means for impressing current on some of said circuit connections to start the operation of said motors.

54. A telegraph system including a plurality of stations, circuit connections between said stations, telegraph apparatus at said stations, motors at said stations for driving said telegraph apparatus, and manually operable means for interconnecting said stations for communication purposes and for simultaneously impressing current on some of said circuit connections to start the operation of said motors.

55. In a telegraph system in combination, a plurality of telegraph -stations, circuit connections between said stations, telegraph apparatus and control means for starting the operation of said telegraph apparatus from a remote point associated with said circuit connections at said stations, and manually operable means for establishing communication circuits between said stations and for applying current to some of said circuit connections to operate said control means.

56. In a telegraph system in combination, a plurality of telegraph stations, circuit connections between said stations, motors and telegraph apparatus at said stations, relay means associated with said circuit connections for controlling the operation of said motors and telegraph apparatus, and manually operable means for interconnecting said stations for communication purposes and for impressing current on some of said circuit connections to operate said relay means.

57. A telegraph system including a plurality of telegraph stations, circuit connections between said stations, telegraph apparatus at said stations, normally non-operating motor means at said stations for driving said telegraph apparatus, manually operable means at one of said stations for interconnecting said stations for communication purposes, means controlled by the operation of said manually operable means for impressing current on some of said circuit connections, and means at said stations operated by said current for starting said motor means into operation.

58. A telegraph system including a plurality of telegraph stations, circuit connections between said stations, telegraph apparatus at said stations, motors at said stations for driving said telegraph apparatus, switching means for interconnecting the telegraph apparatus at said stations for communication purposes, and means associated with said switching means for impressing current on some of said circuit connections to start the operation of said motors.

59. A telegraph system including a plurality of stations, circuit connections between said stations, telegraph apparatus at said stations, motors at said stations for driving said telegraph apparatus, and means for interconnecting said stations for communication purposes and for simultaneously impressing current on some of said circuit connections to start the operation of said motors.

60. In a telegraph system in combination, a plurality of telegraph stations, circuit connections between said stations, telegraph apparatus and control means for starting the operation of said telegraph apparatus from a remote point associated with some of said circuit connections at said stations, and means for establishing communication circuits between said stations and for applying current to some of said circuit connections to operate said control means.

61. In a telegraph system in combination, a plurality of telegraph stations, circuit connections between said stations, motors and telegraph 1 apparatus at said stations, relay means associated with some of said circuit connections for controlling the operation of said motors and telegraph apparatus, and switching means for interconnecting said stations for communication purposes 1 and for impressing current on some of said circuit connections to operate said relay means.

62. 'A telegraph system including a plurality of telegraph stations, line wires between said stations, telegraph apparatus at said stations, normally non-operating motor means at said stations for driving said telegraph apparatus, switching means at one of said stations for interconnecting said one station with any one of a plurality of stations for intercommunication purposes, means controlled by said switching means to impress current on some of said line wires, and means at the selected station operated by said current for starting said motor means into operation. r

63. Means for controlling the operation of printing telegraph apparatus from a remote point comprising in combination, a motor-control circuit extending from said telegraph apparatus to a control point, a communication circuit extending from said'telegraph apparatus to said control point, relay means associated with said control circuit at said telegraph apparatus, and common means at said control point for switching said communication circuit and for applying current to said control circuit to control the operation of said telegraph apparatus through the operation of said relay means.'

64. In a telegraph signalling system, a plurality of stations, a drive motor at each of said sta- 3 tions normally at rest, and means at one of said stations for selectively starting said motors into operation.

65. In a telegraph signalling system, a plurality of stations, a drive motor at each of said stations normally at rest, and means at one of said stations for selectively starting and stopping said motors.

66. A telegraph system including a plurality of stations, circuit connections between said stations, non-operative telegraph apparatus at said stations, manually operable means for interconnecting the telegraph apparatus at said stations for communication purposes, and means for applying current to said circuit connections to render operative said telegraph apparatus.

67. In atelegraph system in combination, a plurality of telegraph stations, circuit connections between said stations, non-operative telegraph apparatus at said stations, manually operable means for interconnecting said stations for communication purposes, means for impressing current on said circuit connections, and means associated with said telegraph apparatus and responsive to said current for rendering operative said telegraph apparatus.

, 68. A system for telegraph apparatus comprising a plurality of stations, a transmitter at one of said stations, receivers at the others'of said stations, a common intercommunicating circuit, and means at said transmitter for connecting any one or more of said receivers to said circuit in relation for intercommunication.

69. A telegraph system comprising a plurality of stations, a common intercommunicating circuit, and switching means at one of said stations for selectively connecting any desired ones of the stations to said circuit in relation for intercommunication.

70. A telegraph system comprising a plurality of stations, circuit-switching means at one of said stations for connecting any one or more of said stations in a common intercommunicating connection and for supplying electrical signalling energy to said common connection.

'71. In a telegraph system, a plurality of stations, lines associated with said stations, a link circuit at one of said stations normally disconnected from all of said lines, a source of telegraph signalling current connected in said link circuit, and means associated with said link circuit for connecting said link circuit to any desired number of said lines.

72. A telegraph switching system comprising a first station equipped with telegraph sending means and a plurality of other stations each equipped with telegraph receiving means, lines extending from each said other station to said first station, a plurality of two-position station keys individual to said lines at said first station, and means including station keys whereby said telegraph sending means at said first station may send individually to any said other station, and whereby said sending means may broadcast to any or all of said other stations.

73. A telegraph system including a plurality of stations, circuit connections between said stations, telegraph apparatus at said stations, manually operable means for interconnecting the telegraph apparatus at said stations for communication purposes, and means responsive to the operation of said manually operable means to control the operation of said telegraph apparatus.

74. In a telegraph system comprising a plurality of stations, means for selectively interconnecting one of said stations with one'or more other stations in a communicating circuit; and a motor at one of said stations controlled by said interconnecting means.

75. A telegraph system comprising a plurality of stations, manually operable meansfor selectively interconnecting any one of said stations with another of said stations in a communicating circuit; and a motor at one of said stations controlled by said manually operable means.

'76. A switching system forprinting telegraph circuits comprising a first and a second station each provided with a printer normally open-circuited when not in use, circuit arrangements controlled at each station whereby the two printers may be connected together in a closed circuit, said arrangements being characterized by two parallel conducting paths extending between the stations, one of said paths being normally connected to the printer at the first station and open-circuited at the second station, and the other of said paths being normally connected to the printer at the second station and open-circuited at the first station, and a switching device at each station for controlling each of said circuit arrangements and for connecting the local printer to the path normally open-circuited at the local station.

77. A switching system for printing telegraph circuits comprising a plurality of stations each provided with a printer normally open-circuited when not in use, circuit arrangements controlled at each of said stations whereby any two printers may be connected together in a closed circuit, said arrangements including two parallel conducting paths extending between any two said stations, one of said paths being normally connected to the printer at a first station and open-circuited at a second station, and the other of said paths being normally connected to the printer at the second station and open-circuited at the first station, a switching device for controlling each of said circuit arrangements at each of said stations and for connecting the local printer to the path normally open-circuited at the latter station, and a second switching device at each of said stations for controlling two or more circuit arrangements at a station whereby the printer at a local station may be simultaneouslyconnected to two or more printers at different stations for broadcast purposes.

'78. A switching system according to claim '76 wherein the driving motors of the printers at two or more stations interconnected by closed paths are controlled by the first mentioned switching devices at the originating station.

'79. A switching device according to claim 76 wherein the first mentioned switching devices at a station are arranged to be selectively operated when said second mentioned switching device at the same station is operated to provide selective broadcasting.

80. A telegraph system comprising a plurality of stations, means for interconnecting any one of said stations with any other one or more of tions, signalling lines interconnecting said trans- 1 mitting station and said receiving stations, manually operable switching means at said transmitting station for interconnecting said transmitting station with said receiving stations, and further means operated by said manually operable switching means preventing substantial change in resistance in the signalling circuit.

83. In a telegraph switching system, a transmitting station, a plurality of receiving stations, line wires individual to each of said receiving stations, and means at the transmitting station for connecting three or more of the receiving stations in a common signalling system with said transmitting station and including'said line wires of the connected receiving stations.

84. In a' telegraph switching system, a transmitting station, a plurality of receiving stations signalling channels individual to each of said receiving stations, and means at the transmitting station for connecting any one or more of the receiving stations in a common signalling system with said transmitting station and including the signalling channels of the connected receiving stations.

85. In a telegraph switching system, a transmitting station, a plurality of receiving stations, signalling channels individual to each of said receiving stations, means at the transmitting station for connecting any one or more of the receiving stations in a common signalling system with said transmitting station including the signalling channels of the connected receiving stations, and means at the receiving stations responsive to the interconnections for rendering the apparatus thereat responsive to signals from the transmitting station.

86. A telegraph system comprising a first station, a plurality of other stations, telegraph apparatus ateach 'of said other stations, a motor at each of said other stations, line wires connecting said first station to each of said other stations, mechanical switching means at said first station having contacts for interconnecting said first station and one of said other stations in a communication circuit, further contacts in said mechanical switching means, and a motor-controlling device controlled by said further contacts.

HOWARD K. CARROLL. 

